Abstract: An antenna system includes an antenna and an antenna control apparatus. The antenna control apparatus includes a control circuit, i.e., a control integrated circuit. The control circuit adjusts and boosts an antenna voltage to supply a required current to the antenna. The antenna voltage is maintained so as not to exceed a predetermined upper limit voltage threshold value. The control circuit is configured to determine a disconnection failure on the antenna when the antenna voltage detected by an overvoltage detection circuit reaches the upper limit voltage threshold value, or is boosted beyond the upper limit voltage threshold value.

Abstract: An antenna system includes an antenna and an antenna control apparatus. The antenna control apparatus includes a control circuit, i.e., a control integrated circuit. The control circuit adjusts and boosts an antenna voltage to supply a required current to the antenna. The antenna voltage is maintained so as not to exceed a predetermined upper limit voltage threshold value. The control circuit is configured to determine a disconnection failure on the antenna when the antenna voltage detected by an overvoltage detection circuit reaches the upper limit voltage threshold value, or is boosted beyond the upper limit voltage threshold value.

Abstract: An authentication system includes an authentication target device used in an authentication target and a plurality of portable devices each carried by a user. The authentication target device performs wireless communication with each of the plurality of portable devices and controls the authentication target by a verification via the wireless communication. The authentication target device includes an authentication target transmitter configured to transmit a radio wave carrying a signal, an authentication target receiver configured to receive a radio wave carrying a signal, and a registration unit configured to register the plurality of portable devices that are genuine. Each of the plurality of portable devices includes a portable device transmitter configured to transmit the radio wave carrying the signal and a portable device receiver configured to receive the radio wave carrying the signal.

Abstract: An authentication system includes an authentication target device used in an authentication target and a plurality of portable devices each carried by a user. The authentication target device performs wireless communication with each of the plurality of portable devices and controls the authentication target by a verification via the wireless communication. The authentication target device includes an authentication target transmitter configured to transmit a radio wave carrying a signal, an authentication target receiver configured to receive a radio wave carrying a signal, and a registration unit configured to register the plurality of portable devices that are genuine. Each of the plurality of portable devices includes a portable device transmitter configured to transmit the radio wave carrying the signal and a portable device receiver configured to receive the radio wave carrying the signal.